Flutter - Battery Level and State

import 'dart:async';

import 'package:flutter/material.dart';
import 'package:battery_plus/battery_plus.dart';

import 'dart:async';

import 'package:flutter/material.dart';
import 'package:battery_plus/battery_plus.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: const MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({
    Key? key,
  }) : super(key: key);

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  var battery = Battery();
  int percentage = 0;
  late Timer timer;

  // created a Batterystate of enum type
  BatteryState batteryState = BatteryState.full;
  late StreamSubscription streamSubscription;
                                                                             

  @override
  void initState() {
    super.initState();
    // calling the method to get battery state
    getBatteryState();

    // calling the method to get battery percentage
    Timer.periodic(const Duration(seconds: 5), (timer) {
      getBatteryPerentage();
                                                        
    });
    
                                                       
  }
  // method created to display battery percent
  void getBatteryPerentage() async {
    final level = await battery.batteryLevel;
    percentage = level;

    setState(() {});
  }

  // method to know the state of the battery
  void getBatteryState() {
    streamSubscription = battery.onBatteryStateChanged.listen((state) {
      batteryState = state;

      setState(() {});
    });
  }

// Custom widget to add different states of battery
// ignore: non_constant_identifier_names
  Widget BatteryBuild(BatteryState state) {
    switch (state) {

      // first case is for battery full state 
      // then it will show green in color
      case BatteryState.full:
        // ignore: sized_box_for_whitespace
        return Container(
          width: 200,
          height: 200,
          
          // ignore: prefer_const_constructors
          child: (Icon(
            Icons.battery_full,
            size: 200,
            color: Colors.green,
          )),
        );

       // Second case is when battery is charging
       // then it will show blue in color
      case BatteryState.charging:
        
        // ignore: sized_box_for_whitespace
        return Container(
          width: 200,
          height: 200,
          
          // ignore: prefer_const_constructors
          child: (Icon(
            Icons.battery_charging_full,
            size: 200,
            color: Colors.blue,
          )),
        );

        // third case is when the battery is
        // discharged then it will show red in color
      case BatteryState.discharging:
      default:
        
        // ignore: sized_box_for_whitespace
        return Container(
          width: 200,
          height: 200,
          
          // ignore: prefer_const_constructors
          child: (Icon(
            Icons.battery_alert,
            size: 200,
            color: Colors.red,
          )),
        );
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        backgroundColor: Colors.green,
          title: const Text('GeeksforGeeks',
                            style: TextStyle(color: Colors.white),),
          centerTitle: true,
      ),
      body: Center(
        child: Column(
          
          mainAxisAlignment: MainAxisAlignment.center,
          children:[
            
            // calling the custom widget
            BatteryBuild(batteryState),
            
            // Displaying battery percentage
            Text('Battery Percentage: $percentage',
                 style: const TextStyle(fontSize: 24),)
            ],
        ),
      ),
    );
  }
}